10-Propargyl-10-deazaaminopterin (variously referred to herein as “10-propargyl-10-dAM”, “pralatrexate” or “PDX”) is a member of a large class of compounds which have been tested and in some cases found useful in the treatment of cancer. This compound, which has the structure shown in FIG. 1, was disclosed by DeGraw et al., “Synthesis and Antitumor Activity of 10-Propargyl-10-deazaaminopterin,” J. Med. Chem. 36: 2228-2231 (1993) and shown to act as an inhibitor of the enzyme dihydrofolate reductase (“DHFR”) and as an inhibitor of growth in the murine L1210 cell line. In addition, some results were presented for the antitumor properties of the compound using the E0771 murine mammary tumor model.
U.S. Pat. No. 6,028,071 and PCT Publication No. WO 1998/02163, incorporated herein by reference in their entireties, disclose the surprising observation that more highly purified PDX compositions when tested in a xenograft model for their efficacy against human tumors have now been shown to be far superior to methotrexate (“MTX”) and are even superior to edatrexate (“EDX”), a more recent clinical candidate. Moreover, PDX showed a surprising ability to cure tumors such that there was no evidence of tumor growth several weeks after the cessation of therapy. Thus, a highly purified composition containing PDX can be used in accordance with the invention to treat tumors, including both solid tumors and leukemias. The composition is illustrated for use in treatment of human mammary tumors and human lung cancer.
Subsequent studies with PDX have shown that it is useful on its own and in combinations with other therapeutic agents. For example, Sirotnak et al., Clinical Cancer Research Vol. 6, 3705-3712 (2000) reports that co-administration of PDX and probenecid, an inhibitor of a cMOAT/MRP-like plasma membrane ATPase greatly enhances the efficacy of PDX against human solid tumors. PDX and combinations of PDX with platinum based chemotherapeutic agents have been shown to be effective against mesothelioma. (Khokar, et al., Clin. Cancer Res. 7: 3199-3205 (2001). Co-administration with gemcitabine (Gem), for treatment of lymphoma, has been disclosed in WO/2005/117892 (incorporated by reference herein in its entirety). Combinations of PDX with taxols are disclosed to be efficacious in U.S. Pat. No. 6,323,205, also incorporated by reference in its entirety. PDX has also shown to be effective for treatment of T-cell lymphoma, see U.S. Patent Application Publication No. 2005/0267117, also incorporated by reference herein in its entirety. Other studies have shown a method for assessing sensitivity of a lymphoma to treatment with PDX by determining the amount of reduced folate carrier-1 enzyme (RFC-1) expressed by the sample, wherein a higher level of expressed RFC-1 is indicative of greater sensitivity to 10-propargyl-10-dAM, disclosed in PCT Publication No. WO 2005/117892, which is incorporated by reference herein in its entirety.
Non-small cell lung cancer (“NSCLC”) is the most common of the advanced solid tumors. It is usually treated by surgery or radiation therapy. Targeted therapies utilizing drugs such as erlotinib (Tarceva®) have also been used in some patients. NSCLC refers to a subset of cancer types that account for approximately 70% of lung cancers, including squamous cell carcinoma of the lung, large cell carcinoma of the lung, and adenocarcinoma of the lung. There are more than 1.2 million new cases of lung and bronchial cancer each year worldwide, causing approximately 1.1 million deaths annually. According to the American Cancer Society, lung cancer is the most common cancer-related death in both men and women. An estimated 162,460 deaths, accounting for about 29 percent of all cancer deaths, are expected to occur in the U.S. in 2006. In Europe, it is estimated that there were approximately 381,500 new cases of lung cancer in 2004 and 936 deaths every day. Lung cancer is reported to be the single largest cause of cancer deaths in the world, responsible for 17.6 percent of all cancer deaths.
Tarceva® (FIG. 2) is a small molecule human epidermal growth factor type 1/epidermal growth factor receptor (HER1/EGFR) inhibitor which demonstrated, in a Phase III clinical trial, an increased survival in advanced NSCLC patients. Tarceva® is a small molecule designed to target the human epidermal growth factor receptor (HER1) pathway, which is one of the factors critical to cell growth in non-small cell lung and pancreatic cancers. HER1, also known as EGFR, is a component of the HER signaling pathway, which plays a role in the formation and growth of non-small cell lung and pancreatic cancers. Tarceva® is designed to inhibit the tyrosine kinase activity of HER1/EGFR, thereby impeding the HER1/EGFR signaling pathway inside the cell. Tarceva® (also known as erlotinib) has the IUPAC name N-(4-ethynylphenyl)-6,7-bis(2-methoxyethoxy)quinazolin-4-amine hydrochloride[6,7-bis(2-methoxyethoxy)-4-quinazolin-4-yl]-(3-ethynylphenyl)amine (also known as OSI-774, erlotinib, or Tarceva® (erlotinib HCl); OSI Pharmaceuticals/Genentech/Roche) (U.S. Pat. No. 5,747,498; International Patent Publication No. WO 01/34574, and Moyer, J. D. et al. (1997) Cancer Res. 57:4838-4848); C1-1033 (formerly known as PD183805; Pfizer).
A need still remains in the art for better treatments for NSCLC. These and other needs are addressed by the present invention. All references cited herein, both supra and infra, are hereby incorporated by reference herein in their entireties.